A unique offering in Dr. z’s ever expanding line of hand-wired tube amps, the Z-Plus resulted from a request by Joe Walsh for a new amp to use on the Eagles’ 2018 tour. Walsh famously used small Fender tweed combos on many of his legendary recordings, so the starting point for Dr. Z’s Mike Zaite was classic single-ended class-A architecture, but with his own twists on a design that would also reflect Walsh’s appreciation for vintage hi-fi audio amps.
The result was the Z-Plus, a parallel single-ended amplifier that uses two 6V6 power tubes in true class-A configuration. Imagine two single-tube tweed amps in one package and you’ve got the idea. Of course, bringing the concept into something befitting Dr. Z required that the amp be its own thing, so along with a half-power switch, tube-driven reverb, and an effects loop, the circuit housed within the custom aluminum chassis also reflects the builder’s typically high level of quality and attention to detail. The hand-soldered connections on the terminal board are neat, and the list of top-grade components includes German-made F&T electrolytic caps, a PEC pot for volume control (the other pots are Alphas) and an output transformer made especially for this amp that uses highest-grade M-6 stacked laminates. (Stacking factor is the ratio of the actual volume of steel in a transformer stack—not including air or insulating materials—compared to the measured dimension of the stack. The M-6 designation means that the laminations are smoothly finished everything else in the assembly process has been optimized to produce a very high-grade unit.)
The Z-Plus LT Combo on review here has a slightly larger cabinet (22.5” wide x 19.5 high x 10.5” deep) than the Studio Combo version, and is available with the standard, Eminence-made Z 12 speaker or a Celestion